JPH04277660A - Integrated circuit package - Google Patents

Abstract

PURPOSE:To prevent a defective due to an (unfilled) gap of plastic resins by implanting resins from a groove of a heat sink. CONSTITUTION:An integrated circuit chip 4 is placed in a heat sink 2 and connected to one of leads 3. This heat sink 2 is inserted into a sealing metal mold 6 to be resin-sealed. At least one of grooves 12 to 14 which extend from the side of a gate 8 of the sealed metal mold 6 is provided on a rear surface of the heat sink 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to integrated circuit packages, and more particularly to the structure of heat sinks thereof.

0002

2. Description of the Related Art The structure of a conventional integrated circuit package with an insulated heat sink is shown in perspective views and sectional views taken along line A-A' in FIGS. 3(a) and 3(b).

This integrated circuit package has an integrated circuit chip 4 placed on a heat sink 2 to which leads 3 are attached, and covered with a molding resin 1. On the back surface of the heat sink 2, the mold resin 1 has a thin resin layer 5 having a thickness of 0.1 to 0.3 mm.

[0004] This thin resin layer 5 is a heat sink 2 of an integrated circuit.
Although it is provided for the purpose of electrically insulating the integrated circuit package 4 from the outside, it is also necessary to release the heat generated during the operation of the integrated circuit package 4 to the outside via the heat sink 2 and the resin layer 5.
It is necessary to make it as thin as possible, that is, to keep the thermal resistance low. The heat dissipation plate 2 is made into a flat plate mainly made of copper.

[0005]

SUMMARY OF THE INVENTION As described above, in the package with an insulated heat sink, it is necessary to form the resin thickness of the back surface of the heat sink 2 to be as thin as 0.1 to 0.3 mm. This leads to frequent failures such as unfilled resin in the encapsulation process in which the heat sink 2 and the integrated circuit chip 4 mounted on the heat sink are encapsulated with the mold resin 1 in the manufacturing process of the integrated circuit package. Therefore, it is a factor that significantly deteriorates the manufacturing yield. This non-filling failure occurs because the resin enters the portion of the back surface of the heat sink where the thin resin layer 5 is formed slowly during the sealing process.

FIGS. 4(a) and 4(b) show cross-sectional views during the encapsulation process. In this case, resin is shown being injected into the cavity 9 from the gate 8 of the encapsulation mold 6. The cavity 9 on the back surface of the heat sink 2 has a narrow gap 7, and the mold resin 1a enters the cavity 9 much more slowly than other parts. Therefore, as shown in FIG. 4(b), the resin enters the back surface of the heat sink 2 from the part other than the gate 8 side, and in order to seal the air, a void 11, that is, an unfilled part, is very likely to be formed. The yield of the process is significantly deteriorated.

[0007] In order to prevent the formation of voids 11, some methods have been adopted in which the shape of the gate portion 8 of the encapsulation mold 6 is devised to control the injection direction of the resin, and some effects have been observed. However, no fundamental solution has been reached.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an integrated circuit package that solves these problems, prevents defects due to unfilled molding resin, and improves manufacturing yield.

[0009]

[Means for Solving the Problems] The structure of the present invention is an insulated heat sink in which a heat sink on which an integrated circuit chip is mounted and connected to one lead is inserted into an encapsulating mold and sealed with a resin. In the integrated circuit package with
It is characterized in that at least one groove extending from a portion of the gate side of the encapsulation mold is provided on the back surface thereof.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1(a) and 1(b) are perspective views of a heat sink used in an embodiment of the present invention, and sectional views for explaining the injection process. Here, the back surface of the heat sink 2 is shown facing up and the front surface (the surface on which the integrated circuit chip 4 is mounted) is facing down.

As shown in FIG. 1(a), this heat sink 2 has a width of about 0.1 to 0.5 mm and a depth of 0.1 mm on the back side.
~0.5 mm, length is 50~ of the heat sink length
Approximately 80% of the grooves 12 to 14 are provided. Three grooves 12 to 14 are provided in the direction in which the resin enters in the encapsulation process.

In the encapsulation process of this example, FIG.
), the groove 13 is naturally connected to the enclosing mold 6 and the heat sink 2.
The gap becomes wider, promoting the entry of resin in this area, and the resin that enters the groove gradually spreads to other parts than the groove, and as a result, resin entry into the entire back of the heat sink is promoted. become.

Therefore, it is possible to solve the problem that the resin enters the back side of the heat sink 1 slowly, causing the resin to wrap around from other parts and trapping air.

FIG. 2 shows a perspective view of a heat sink used in a second embodiment of the present invention. In this embodiment, the shapes of the end portions of the grooves 12 to 13 of the heat sink 2 are widened to provide openings 15. This opening 15 can further promote entry of the resin into the grooves 12 to 14 during the sealing process.

In this case, by providing the grooves 12 to 14, the area of the thin resin portion 5 on the back side of the heat sink 2 becomes smaller than that of the conventional structure, and there is a concern that the thermal resistance will become relatively large. However, if the area of the grooves 12 to 14 is set to a few percent or less of the entire area of the heat sink 2, there will be almost no problem in practice.

[0016]

As explained above, the present invention can prevent unfilled defects in the encapsulation process of integrated circuit packages with insulated heat sinks by providing grooves in the heat sink to facilitate resin injection, thereby improving device yield. It has the effect of improving the

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a perspective view of a heat sink used in an embodiment of the present invention and a cross-sectional view when assembled.

FIG. 2 is a perspective view of a heat sink used in a second embodiment of the present invention.

FIGS. 3(a) and 3(b) are a perspective view and a sectional view of a conventional integrated circuit.

4A and 4B are cross-sectional views illustrating the enclosing process of FIG. 3;

[Explanation of symbols]

1, 1a Mold resin 2 Heat dissipation plate 3 Lead 4 Integrated circuit chip 5 Thin resin layer 6 Encapsulation mold 7 Cavity gap 8 Gate section 9 Cavity section 11 Gaps 12 to 14 created in the cavity
Groove 15 Opening

Claims (1)

[Claims] 1. An integrated circuit package with an insulated heat sink in which a heat sink on which an integrated circuit chip is mounted and connected to one lead is inserted into an encapsulating mold and sealed with a resin, wherein the heat sink is , wherein at least one groove extending from a portion of the gate side of the encapsulating mold is provided on the back surface thereof.